CVE-2026-42272
Heimdall: Case-sensitive handling of URL-encoded slashes may lead to inconsistent path interpretation
Description
Heimdall is a cloud native Identity Aware Proxy and Access Control Decision service. Prior to version 0.17.14, Heimdall handles URL-encoded slashes (%2F) in a case-sensitive manner, while percent-encoding is defined to be case-insensitive. As a result, the lowercase equivalent (%2f) is not recognized and therefore not processed as expected when allow_encoded_slashes is set to off (the default setting). This discrepancy can lead to differences in how request paths are interpreted by heimdall and upstream components, which may result in authorization bypass. This issue has been patched in version 0.17.14.
INFO
Published Date :
May 8, 2026, 4:16 a.m.
Last Modified :
May 8, 2026, 4:16 a.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 4.0 | HIGH | [email protected] |
Solution
- Update Heimdall to version 0.17.14 or later.
- Verify allow_encoded_slashes setting behavior.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-42272.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-42272 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-42272
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
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The following list is the news that have been mention
CVE-2026-42272 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-42272 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by [email protected]
May. 08, 2026
Action Type Old Value New Value Added Description Heimdall is a cloud native Identity Aware Proxy and Access Control Decision service. Prior to version 0.17.14, Heimdall handles URL-encoded slashes (%2F) in a case-sensitive manner, while percent-encoding is defined to be case-insensitive. As a result, the lowercase equivalent (%2f) is not recognized and therefore not processed as expected when allow_encoded_slashes is set to off (the default setting). This discrepancy can lead to differences in how request paths are interpreted by heimdall and upstream components, which may result in authorization bypass. This issue has been patched in version 0.17.14. Added CVSS V4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CWE CWE-436 Added CWE CWE-178 Added Reference https://github.com/dadrus/heimdall/commit/8b0de6aba23a047cfee3081df878271bb17f4351 Added Reference https://github.com/dadrus/heimdall/pull/3207 Added Reference https://github.com/dadrus/heimdall/releases/tag/v0.17.14 Added Reference https://github.com/dadrus/heimdall/security/advisories/GHSA-43jv-5j4x-qv67